I use POR-15 on my frame and a chassis parts. If flows so well, even painted on with a brush it glosses up like it was sprayed on. It does have some nasty attributes, so I would rather brush it than spray it. Either way, make sure you use resporator and keep area well ventilated.

I will also be using the POR-15 inside the car on the floorboards with faberglass matt to give the whole car more rigidity. It also improves sound deadening and the POR and fiberglass matt give a nice texture finish. I also use the POR and fiberglass matt to seal and cover wooden speaker boxes in the body panels. Also one behind the rear seat for a sub-woofer. Sealed wood enclosures put out some great sound. The POR also flowes through the fiberglass matt much better than resin does.

POR also has Metal Ready which is an acid base rust remover and etching agent. Makes the POR-15 bond very well. They also carry Marine Clean for final prep before painting.

I find the POR-15 to be tougher than powder coating

Dean